xdf(CD)-Sec6-12&13

12-13

12.Meteorologists say that if only they could design an accurate mathematical model of the atmosphere with all its complexities, they could forecast the weather with real precision. But this is an idle boast, immune to any evaluation, for any inadequate weather forecast would obviously be blamed on imperfections in the model.

Which of the following, if true, could best be used as a basis for arguing against the author’s position that the meteorologists’ claim can not be evaluated?

(A)  Certain unusual configurations of data can serve as the basis for precise weather forecasts even though the exact causal mechanisms are not understood.

(B)   Most significant gains in the accuracy of the relevant mathematical models are accompanied by clear gains in the precision of weather forcasts.

(C)  Mathematical models of the meteorological aftermath of such catastrophic events as volcanic eruptions are beginning to be constructed.

(D)  Modern weather forecasts for as much as a full day ahead are broadly correct about 80 percent of the time

(E)   Meteorologists readily concede that the accurate mathematical model they are talking about is not now in their power to construct

13.Which of the following, if true, would cast the most serious doubt on the meteorologists’ boast, aside from the doubt expressed in the passage above?

(A)   The amount of energy that the Earth receives from the Sun is monitored closely and is known not to be constant.

(B)   Volcanic eruptions, the combustion of fossil fuels, and several other processes that also can not be quantified with any accuracy are known to have a significant and continuing impact on the constitution of the atmosphere

(C)   As current models of the atmosphere are improved, even small increments in complexity will mean large increases in the number of computers required for the representation of the models.

(D)   Frequent and accurate data about the atmosphere collected at a large number of points both on and above the ground are a prerequisite for the construction of a good model of the atmosphere

(E)   With existing models of the atmosphere, large scale weather patterns can be predicted with greater accuracy than can relatively local weather patterns.

Keys: 12-B; 13-B

Pls tell me how to solve these two questions. appreciate it.